military intervention in Syria remains unlikely. Russia will not authorise even a UN arms embargo; Syria's rebels are divided and weak; and the rise of suicide bombings has heightened fears for the safety of any intervention force. There are three potential game-changers, though.
First, Syria's chemical weapons stockpile could be a flashpoint, if Damascus seemed to be losing control of its sites.
The second trigger could be a change in Turkey's position. If Turkey announced it was carving humanitarian corridors into Syria, it might change the western calculus, particularly if Arab states were open to contributing manpower. The third trigger might be another highly visible massacre -- but only in conjunction with a strengthening of the rebels' position.
Shashank Joshi is a research fellow of the Royal United Services Institute